The rare and beloved pitch-pine ecosystem is facing a threat brought on by global warming: the Southern pine beetle (SPB). Increasingly warmer temperatures have resulted in the SPB moving north over the last eight years, and beginning to feast on already-delicate pine barren ecosystems, primarily on Long Island and parts of New Jersey. But last week the New York State Department of Environmental Conservation (DEC), along with the Office of Parks, Recreation and Historic Preservation (OPRHP), announced that “Southern pine beetles were found farther north than previously documented and in greater numbers, suggesting their range is expanding and populations are on the rise.” According to the DEC, the SPBs are “destructive forest pests that pose a significant threat to the State’s pine forests, particularly pitch pine forests like those found in the Albany Pine Bush and Minnewaska State Park.”
OPRHP commissioner Erik Kulleseid stated that in his estimation, “The Southern pine beetle poses a real threat to some of our most fragile ecosystems and iconic landscapes,” of which he included Minnewaska, Sam’s Point Preserve, Schunnemunk Mountain State Park, the Hudson Highlands and Taconic State Park. “We will continue to partner with DEC to identify potential SPB infestations, allowing us the ability to react quickly and hopefully mitigating any large-scale damage before it occurs.”
Pine barrens are a globally rare ecosystem, and most of the plants and animals that thrive in this particular habitat are considered rare and unique, including the pitch pine and the dwarf pine. Species likely to be found in the pitch-pine barrens in the Hudson Valley region include the frosted elfin butterfly, the Northern long-eared bat and the Eastern whip-poor-will. Some notable plant species are Appalachian sandwort, mountain sandwort and Schweinitz’s flat sedge.
Native to the southeastern US, SPB was first discovered infesting pitch pines on Long Island in 2014. Since that time, The DEC has reported that the SPB has “killed hundreds of thousands of trees on Long Island alone.”
What triggered the press release was the discovery of an increase of SPBs in traps at Schunnemunk, Minnewaska and Taconic State Parks, put there by the DEC and OPRHP in an effort to monitor SPB movement. Dan Keefe, a public information officer for OPRHP, said that the first Southern pine beetle was detected at Minnewaska in 2019. “We have had small numbers of Southern pine beetle caught in the Hudson Valley traps for the past few years. We saw a noticeable increase in 2021 on Schunnemunk Ridge, but the uptick was across all of the traps in the Hudson Valley.”
According to Keefe, they use a Lindgren-style funnel trap with pheromone lures. He was quick to note that catching SPBs in a trap is not “an infestation. No infested trees have been found at Minnewaska or Sam’s Point Preserve. Ground surveys are happening and will continue throughout the growing season.”
The pitch pine is a signature species at both the Minnewaska and Sam’s Point Preserves. At Sam’s Point, there are dwarf pitch pines, made smaller by exposure, high winds and acidic soil. Asked whether or not the dwarf pines would be more susceptible to an infestation, Keefe said, “While we have seen dwarf trees attacked in the dwarf pine plains on Long Island, SPBs are less able to amass a large-enough population for an infestation to reach outbreak. Infestations are likely to fizzle without the presence of larger, suitable brood trees.” In short, he said, the dwarf pines are less likely to be susceptible to an SPB attack.
Hudson Valley One also reached out to Minnewaska State Park’s neighbor, the Mohonk Preserve. Both help to protect and preserve more than 32,000 combined acres of the Shawangunk Ridge and the foothills and watersheds that surround it. Although conservation staff are aware of the SPB, they’ve had no confirmed signs of any SPB activity on the Preserve lands to date. As part of the Shawangunk Ridge Biodiversity Partnership, which includes the DEC and OPRHP, the Preserve said that the SPB will be a “topic for discussion at an upcoming meeting.”
In terms of any ongoing monitoring program, similar to the ones that the DEC and OPRHP have been working on in various pitch-pine forest lands, Preserve forest ecologist Kate O’Connor said that “The Preserve has established long-term forest health monitoring plots throughout our lands, including pitch-pine areas, which record the presence of forest pests among other measures of forest health. This year we are kicking off a targeted Southern pine beetle monitoring program.”
In terms of the best prevention, O’Connor said that early detection and overall forest health are the best measures against the SPB or other destructive infestations. “Our goal is to maintain healthy, resilient pitch-pine forests through an appropriately managed and diverse landscape to decrease the likelihood of an outbreak,” she noted. “Good silviculture, coupled with surveys to detect infestations and initiate a rapid response, are the next step.”
According to O’Connor and Keefe, the SPB has a few known enemies including woodpeckers, several species of parasitoid wasp and the dubious checkered beetle (Thanasimus dubius), a native species that is a known predator of the SPB and other bark beetles. “There are a suite of natural predators and parasitoids in the native range of the SPB in the Southeastern US. In New York, there are some predators such as the checkered beetles, members of the Cleridae family, but they do not affect SPB populations greatly.”
How do they attack?
The adult SPB enters the tree through crevices in the bark and then creates S-shaped tunnels in the cambium tissue, just beneath the bark. This disrupts the flow of nutrients and can kill the tree within two to four months. According to the DEC, “Most trees resist the initial attacks by secreting resin that can ‘pitch out’ some adults and slow the entry of others,” which creates a popcorn-sized-and-shaped globule of resin that can be seen on the bark of an infested tree, along with the S-shaped tunnels. While pitch pines can push out various bark beetles and some SPBs, if they become overwhelmed by thousands of attacking beetles, their defenses are weakened and they can die quickly.
While there have been no Southern pine beetles detected at the Preserve and only a small number at Minnewaska State Preserve, with no infestations, Keefe said that the “management plan” would be similar to what they’ve done in Long Island and other pine-barren test areas: “Controlling outbreaks by removing infested trees and managing the forest through thinning and/or fire to prevent outbreaks are the primary strategies being employed.” In fact, They did find three infested trees near Sunset Rock at Taconic State Park and “removed the infested trees and two buffer trees.”
DEC commissioner Basil Seggos concurred. “DEC, in partnership with OPHRP, will continue to proactively work to combat the environmental threats that the SPB poses to New York’s treasured forestland. Our ongoing strategies will help mitigate the impacts of SPB in the Hudson Valley and help slow the spread by removing infested trees and manage susceptible forests using thinning and prescribed fire activities to increase forest health and resiliency.”
Both State agencies and partners fear that more infested pines could be found in the next few years as the climate warms. They’ve conducted controlled burns and felled trees identified to have the SPB infestation, as well as “thinning” the pine barrens to try to keep trees at a distance from one another — a strategy that hasn’t always proven to be successful or necessary, according to their own report (www.dec.ny.gov/docs/lands_forests_pdf/spbannreport2020.pdf, page 8) where they cited occasions when trees were overmarked for SPB infestation and cut down due to “surveyors’ error” and lack of continual monitoring due to the COVID-19 pandemic.
DEC encourages the public to report any signs of SPB encountered in pine forests (outside of Long Island) by e-mailing pictures and location information to email@example.com. The signs of an infestation include discolored needles (yellowing to brownish-red), popcorn-sized clumps of resin called pitch tubes anywhere along the trunk, tiny holes in the bark in a scattershot pattern and S-shaped galleries under the bark. For more information, visit DEC’s Southern Pine Beetle webpage (www.dec.ny.gov/animals/99331.html).